Reciprocating pump



United States Patent 3,148,627 REQIPRGCATING PUMP Theodor Muller, Winterthur, Switzerland, assignor to Schweizerische Lolxornotivand Maschinenfahrik, Winterthur, Switzerland Filed Apr. 18, 1962, Ser. No. 188,432 Qlairns priority, application Switzerland, Apr. 28, 1961, 4,978/61 2 Claims. (Cl. 103-161) The invention relates to a piston pump assembly for delivery of liquids, comprising a pump casing, a cylinder block in which the pistons are guided, a shaft for producing the reciprocating motion of the pistons, admission and delivery ducts for the liquid, and control members for alternately connecting the cylinder spaces with the suction and pressure chambers of the pump.

According to the invention, the pump casing is directly and rigidly connected for rotation with a flange formed on the shaft of the driving motor, while the pump to which the suction and delivery ducts are connected, is maintained stationary at its end projecting from the pump casing.

The accompanying drawings illustrate, by way of example, a radial piston constant stroke lifting pump em bodying the features of the present invention.

FIGURE 1 is an axial section through the pump taken along line I--I of FIGURE 2;

FIGURE 2 represents the pump partly in transverse section along line IIII of FIGURE 1, and partly in elevation in the direction of the arrow A in FIGURE 1.

The casing of the pump consists of the two rotor halves 1 and 2, and is rigidly connected by means of screws 3 to a coupling flange 5 keyed to the motor shaft 4, and accordingly rotates with the motor shaft. A shaft 6 is mounted in ball bearings 7 and 8 carried in the casing 1 and 2. The stationary shaft 6 is provided with a control crank pin 10 which is eccentric relatively to the axis of the shaft. A cylinder block 11 is rotatably mounted on the crank pin 10 and is coupled by means of two auxiliary cranks 12 with the rotor half 1, so as to rotate exactly in synchronism with the rotor casing. Admission and delivery of liquid to and from the cylinders 14 is effected by the alternate connection of the cylinders with the recessed portions 15, 16 respectively, of the control pin 10, which recesses serve as suction and pressure chambers. These chambers are connected by separate ducts 19 and 20 with the suction conduit 21 and the delivery conduit 22, respectively. The pistons 23 have their outer ends 24 slidingly bearing against plates 25. For keeping the frictional forces low, the piston ends can be formed for example, as disclosed in my prior specification No. 2,679,- 210. The two rotor halves 1, 2 are secured together by screws 26.

When the pump operates under pressure, the shaft 6 must be maintained stationary by a torque which is equal 3,148,627 Patented Sept. 15, 1964- ice to the motor torque. For this purpose, use can be made of the delivery conduit 22 which is screwed to the shaft 6 by increasing the strength of the conduit and anchoring it at a point 28 situated at a radial distance 29 from the axis of the shaft. For a motor output of HR and a speed of 1450 rpm. the force to be absorbed by the anchoring 28 at a distance of 0.5 meter from the axis of the shaft 6 amounts to about 100 kgs. only. The distance 30 between the plane where this force is effective and the motor bearing adjacent the pump is to be selected so that the bending moment produced at the motor shaft is not greater than the bending movement exerted by the smallest admissible belt pulley on the motor shaft; this requirement can be met without difficulty in radial piston pumps of axially short overall length.

Instead of the delivery conduit 22, it would be possible also to use the suction conduit 21, which is subjected to less strain, as torque support.

A bore 36 in the shaft 6 communicates with the inner space of the rotor casing 1, 2 by a duct, not shown, and serves for connection with a leak-oil discharge pipe.

The pump assembly according to the invention is distinguished by its simple design and offers the advantage that the rotating pump casing 1, 2 affords an eflicient cooling of the pump.

Instead of connecting the casing portion 1 by means of screws 3 with the coupling flange 5 of the driving shaft 4, the portion 1 and the flange 5 could form an integral part.

I claim:

1. A reciprocating constant delivery fluid pump assembly comprising a driving shaft, a pump drum connected rigidly with said driving shaft, a cylinder block having radial cylinders mounted within said drum and connected to said drum for rotation therewith, a fixed eccentric pin having ducts and control slots for the fluid supporting said cylinder block, a plurality of pistons supported on said drum movable relatively to said cylinders, said pump drum being mounted in overhung position on said driving shaft, a shaft on which said eccentric pin is mounted within said drum aligned with said driving shaft and means maintaining said shaft with said pin stationary, whereby any outer pump casing is rendered superfluous.

2. A reciprocating pump according to claim 1 in which said eccentric pin is maintained stationary by means of a conduit connected to one of said ducts.

References Cited in the file of this patent UNITED STATES PATENTS 2,194,914 Ruch Mar. 26, 1940 2,203,646 Aspden June 4, 1940 2,349,280 Joy May 23, 1944 2,663,264 Michalitsianos Dec. 22, 1953 FOREIGN PATENTS 730,086 Great Britain May 18, 1955 

1. A RECIPROCATING CONSTANT DELIVERY FLUID PUMP ASSEMBLY COMPRISING A DRIVING SHAFT, A PUMP DRUM CONNECTED RIGIDLY WITH SAID DRIVING SHAFT, A CYLINDER BLOCK HAVING RADIAL CYLINDERS MOUNTED WITHIN SAID DRUM AND CONNECTED TO SAID DRUM FOR ROTATION THEREWITH, A FIXED ECCENTRIC PIN HAVING DUCTS AND CONTROL SLOTS FOR THE FLUID SUPPORTING SAID CYLINDER BLOCKS, A PLURALITY OF PISTONS SUPPORTED ON SAID DRUM MOVABLE RELATIVELY TO SAID CYLINDERS, SAID PUMP DRUM BEING MOUNTED IN OVERHUNG POSITION ON SAID DRIVING SHAFT, A SHAFT ON WHICH SAID ECCENTRIC PIN IS MOUNTED WITHIN SAID DRUM ALIGNED WITH SAID DRIVING SHAFT AND MEANS MAINTAINING SAID SHAFT WITH SAID PIN STATIONARY, WHEREBY ANY OUTER PUMP CASING IS RENDERED SUPERFLUOUS. 